Solar energy is a kind of renewable energy source. Using electrical power converted from the solar energy can save power and avoid environment pollution. A junction box in a solar energy system is used for connecting solar cells and external power component to output the power of solar cells.
Generally, a PCB (Printed Circuit Board) in the junction box is installed on a base of the junction box, however, it has some disadvantages which are stated as followed. Firstly, the PCB generates a large quantity of heat in a working condition. The heat is transferred to a body of the junction box by air in the junction box, and then released. The heat is also transferred to the base of the junction box. So the quantity of heat can not be released in time for low thermal conductivity of the air, and this causes temperature rising in the junction box, such to reduce the lifespan of the PCB for a high temperature condition. Meanwhile, the high temperature can accelerate warp and aging of the junction box. Secondly, the PCB, which is installed on the base of the junction box, will fail if water enters into the junction box.
In prior art, a bus bar is used for electrical connection structure between the solar cell and the junction box. One edge of the bus bar is electrically connected to positive or negative electrode of the solar cell, and another edge is electrically connected to the PCB with screws. Meanwhile, the bus bar is installed on the base and the cover is snapped on the base to reinforce the electrical connection structure. An operator must be careful because the bas bars are very thin. So, the structure mentioned above is complex, and resembling work is hard and time consuming.